From: Andrew Jones <drjones@redhat.com>
To: Christoffer Dall <christoffer.dall@linaro.org>
Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, gleb@redhat.com
Subject: Re: [PATCH 0/9] kvm-unit-tests/arm: initial drop
Date: Thu, 2 Jan 2014 19:56:08 +0100 [thread overview]
Message-ID: <20140102185608.GQ9725@hawk.usersys.redhat.com> (raw)
In-Reply-To: <20131229092411.GA14289@cbox>
On Sun, Dec 29, 2013 at 01:24:11AM -0800, Christoffer Dall wrote:
> On Mon, Oct 14, 2013 at 06:23:26PM +0200, Andrew Jones wrote:
>
> Hi Drew,
>
> > This series introduces arm to kvm-unit-tests. First, it does some
> > tidying up of the repo. Then, it adds support for virtio-testdev,
> > which was just posted to qemu-devel[1]. Next, it adds the basic
> > infrastructure for booting a test case (guest). Finally, it adds
> > support for vectors. This is just an initial drop, I'm starting
> > work on smp support now, and then will bring in support for
> > arm64. At that point we should be able to start actually adding
> > tests. To use this you need an arm platform or simulator capable
> > of running kvmarm and a qemu with the mach-virt patches[2], as
> > well as the previously mentioned virtio-testdev.
> >
> > [1] http://lists.nongnu.org/archive/html/qemu-devel/2013-10/msg01815.html
> > [2] http://lists.nongnu.org/archive/html/qemu-devel/2013-09/msg02142.html
> >
> > This patches are also available from a git repo here
> > https://github.com/rhdrjones/kvm-unit-tests/tree/arm-branch/master
> >
>
> I'm playing around with this, thanks again for working on it. It's long
> overdue that we're getting something real done in this area.
>
> I have run into some problems trying to run this thing on real hardware.
> The biggest problem is the known cache coherency issue where we need to
> flush the data cache to make things coherent when the guest runs with
> the MMU disabled. It shows up quite frequently if you just try to run
> the small flat binaries with KVM, and I suspec the only reason we are
> not seeing this with real kernels is that they are large enough that we
> end up writing the necessary data all the way to main memory.
>
> I'm working on a vmexit test to measure stuff, and I noticed that we:
> - really need to find a way to let a guest read the cycle counter
> - need a way to let a call a dummy HVC to KVM to measure round-trip
> times
> - ...
>
> This is probably something we should try to discuss on one of the next
> kvm/arm sync-up calls. I remember something about you not being able to
> make those, but we can arrange a different time for one of them some
> time.
>
> For now, I can work around the cache issue by enabling the DC bits and
> by adding a terrible hack for the cycle counter and dummy HVC. You can
> follow my hackings here:
>
> Kernel:
> https://git.linaro.org/people/christoffer.dall/linux-kvm-arm.git/shortlog/refs/heads/kvm-arm-next-measure
>
> unit-tests:
> https://github.com/columbia/kvm-unit-tests/tree/arm-support
>
> -Christoffer
Thanks Christoffer! I'll look at these branches tomorrow. I'm glad we're
getting some momentum on kvm-unit-tests/arm!
drew
prev parent reply other threads:[~2014-01-02 18:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-14 16:23 [PATCH 0/9] kvm-unit-tests/arm: initial drop Andrew Jones
2013-10-14 16:23 ` [PATCH 1/9] remove unused files Andrew Jones
2013-10-16 12:52 ` Gleb Natapov
2013-10-16 13:13 ` Alexander Graf
2013-10-16 13:18 ` Andrew Jones
2013-10-14 16:23 ` [PATCH 2/9] makefile and run_tests tweaks Andrew Jones
2013-10-14 16:23 ` [PATCH 3/9] clean root dir of all x86-ness Andrew Jones
2013-10-17 1:06 ` Christoffer Dall
2013-10-17 9:35 ` Andrew Jones
2013-10-17 19:01 ` Christoffer Dall
2013-10-20 16:37 ` Andrew Jones
2013-10-14 16:23 ` [PATCH 4/9] Introduce a simple iomap structure Andrew Jones
2013-10-14 16:23 ` [PATCH 5/9] Add halt() and some error codes Andrew Jones
2013-10-14 16:23 ` [PATCH 6/9] Introduce virtio-testdev Andrew Jones
2013-10-15 8:39 ` Andrew Jones
2013-10-17 1:06 ` Christoffer Dall
2013-10-17 9:51 ` Andrew Jones
2013-10-17 19:01 ` Christoffer Dall
2013-10-17 1:06 ` Christoffer Dall
2013-10-14 16:23 ` [PATCH 7/9] arm: replace arbitrary divisions Andrew Jones
2013-10-17 1:06 ` Christoffer Dall
2013-10-17 10:03 ` Andrew Jones
2013-10-17 18:59 ` Christoffer Dall
2013-10-14 16:23 ` [PATCH 8/9] arm: initial drop Andrew Jones
2013-10-17 1:06 ` Christoffer Dall
2013-10-17 10:16 ` Andrew Jones
2013-10-17 13:28 ` Andrew Jones
2013-10-17 18:39 ` Christoffer Dall
2013-10-14 16:23 ` [PATCH 9/9] arm: add vectors support Andrew Jones
2013-10-17 1:06 ` Christoffer Dall
2013-10-17 10:38 ` Andrew Jones
2013-10-17 18:58 ` Christoffer Dall
2013-10-20 16:35 ` Andrew Jones
2013-10-21 9:59 ` Christoffer Dall
2013-11-20 23:06 ` [PATCH 0/9] kvm-unit-tests/arm: initial drop María Soler Heredia
2013-11-26 17:23 ` Andrew Jones
2013-12-29 9:24 ` Christoffer Dall
2014-01-02 18:56 ` Andrew Jones [this message]
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